Belt tightener



Aug. '130, 1927. s. F. STEIN BELT'TIGHTENER Filed Jan. 5. 1918 'g'f//////////////A .Illy

Patented ug. 30, 19.27.

Unirse lSTATES Y PATENT, OFFICE.

SAMUEL F. STEIN, OF WILLIAMSPORT, PENNSYLVANIA.

BELT TIGHTENER.

Application led January 5, 1918. Serial No. 210,453.

The driving mechanism of power driven sewing machinesJ includes belts.These belts become loose or slack in use. When as in the case ofgarmentfactories, a series of machines are driven from one driving shaftand the belt in any one of the series become loose or slack, it isnecessary to stopY the running of all the machines of the series,with'consequent loss of valuable time and likelihood of injury or damageto thev goods being worked on, as will be further explained in detail,or as an alternative to stopping all the machines, the workman must runthe risk from vrotating shafts or other parts, if he undertakes toremedy the slack condition of the belt without stopping themachines.

The obj ect of my invention is to render unnecessary the stoppage of themachines and thereby avoid the loss of time that comes from stoppage and`at thev same time enable the slack condition of any particular sewingmachine belt tof be remedied even by the operative running the machineand without danger of harm or injury from the rotating members.V Underthe usual conditions the work of adjusting loose or slack belts is performed bysome specialmechanic, it being beyond the ability .of thesewing machine operative to do this.

kFor the attainment of my object and to secure other advantages whichwill be apparent to those skilledjin the art when the embodiment of myinvention shown in the drawings is understood, my invention consists inthe construction substantially as hereinafter described and claimed. v

In the accompanying drawings:

1 is across section showing a sewing machine power. table constructionembodying my invention; y

Fig. 2 is a vertical section on the line 2-2 of Fig. 1. A,

Fig. 3'is a horizontal section on the line 3d?) of Fig. 2;

Fig. 1 is a detail view illustrating ay form of automatic .belttightener.

Referring to the drawings I show a vdouble power table of ordinaryconstruction, it comprising cast iron supporting legs 10 and two aliningparallel series of table tops 11, each adapted to support a sewingmachine 12 and having a main driving shaft 13 running longitudinally ofthe series ofv tables and situated betweenl the two series of tables andbeingwdriven continuously by power applied to a band wheel 14 at one endthereof. For

cach sewing machine there is a treadle-controlled transmitter l5 throughwhich power from the continuously running driving shaftv 13 maybetransmitted at the will of the operator .to the' sewing machine, and inthe usual practice there is a pulley 16 for each sewmachine on thedriving shaft 13 belted to a `pulley on the transmitter by a belt 17there is a second pulley on the transmitteribelted by a belt 18 to apulley 19 on the sewing machine shaft adjacent the hand wheel thereof.With such ordinary construction when abelt becomes slack, work on thatmachine must be stopped and the slack condition remedied by cutting outthe surplus portion of the belt and replacing it. Usuallv there is amechanic whose duty it is to look after such matters, and he, of course,may be busy elsewhere, thus prolonging the disuse of thefmachine, and hemust do the work of replacing while the main driving shaft and itspulleys are revolving, and thus is exposedto danger of injury. If, asthe safety laws require, all rotating or moving parts which might exposethe workman to injury mustY be stopped running, then not only the sewingmachine immediately concerned on account of theloose belt, but all ofthemachines that are driven from the same driving shaft are stopped andthus the loss will be multiplied by the number of machines put out ofuse. The importance and valvek of my invention will 'therefore be seenwhen it is understood that no stoppage is necessary, but the work oftaking. care of al slack belt in a particular machine can be performedwhile the driving shaft and the other machines are ruiming and withoutany dan-l yger to the workman concerned doing the work and no specialmechanic is required to do the work, but the voperative on the sewingmachine can do all that is .necessary to take care of the loose or slackcondition." Again the 'matter of stoppage of the sewing machine vis ofimportance in that if it is prolonged there is. likelihood of injuryy toor damage 'of the goods being sewn. If by reason of the lslack conditionof the `belt the machine stops with the work say on a line of stitchingpartially through the machine it would be exposed to the drip of oilfromthe needle bar land if it should be stationary long enough, enough oilwould drip upon it so as to soil or disfigure the goods. By theprovision of a belt tightener and especially one capable of adjustmentor manipulation by Ahe girl; the belt can always be kept in .a propertight condition and it' by inadvertcnce or oversight it should becomeslack and result in stoppage of the machine, the stop need be butmomentary because witha belt tightener such as I provide, the slack canat once be taken up and the running of the machine quickly resumed. Itthe machine stops with the work in it, it would be undesirable to removethe work to prevent injury ifi-om the dropping of oil because of thediiificulty and practical impossibility oit replacing the work in themachine so that the line of stitch. ing would be unbroken.

l provide a belt tightener for the belt 17 which connects the drivingshaft 13 with the tiaiisinittei-and said tightener may consist oi' aroller 2O on the lower end of a shank or lstem 21, which passes througha hole in the table top and through a box 22 secured to the upper sideof the table top and having 'above the latter a set screw 23 forsecuring the shank or stem at the desiredvertical position. It will beseen that although the belt to be tightened is below the table top, yetaccess to the tightener from the top is provided so that convenientlyand quickly the necessary adjustment to the tightener may be had withoutany risk or danger from the running parts of the machinery.

The tightener lor the belt which runs to the sewing machine pulley 19also consists oiE a belt engaging roller 24 anda shank or bar 25 whichcarries the same and I also locate said tightener above the table topand mount it upon the side ot the upright portion oi the sewing machine.head so that it is thereby situated for convenient, easy and sate accessfor manipulation; it is out of the way; and is in el'ect a part of thesewing machine so that if occasion arises 'for moving the sewing machinefrom the t-able and returning it, the tightener .is always carried bythe machine and always in proper position for operat-ioii. I find inmany sewing machines the provision of a` threaded hole 26 in the headbelow the hand wheel and I utilize that hole for the attachment of thetightener to the head. This makes unnecessary the provision ot anyspecial hole and permits of the tightener being applied to machinesalready in use with no alteration of the machine head or trame. I screwin said hole a. threaded bolt or stud 27, and place over the projectingportion of the stud a spacing block 28 of a thickness whichwill bringthe roller-carrying bar in the iight position to secure contact of theroller with the belt, said bar being pivoted on a portion ot said studwhich projects beyond the spacing block. Outside ol the block I apply a.wing nut 29 which serves the purpose of clamping the roller-carrying barat the desired position. Thus one bolt or stud serves as thepivotorrsupport for the roller-carr.'y}

securing the spacing block.

ing bar andthe means for mounting and The rollercarrying bar instead otbeing pivoted to the stud may have a longitudinal slot so thatadjustment Jior tightening the belt is effected by a sliding rather thana. swinging move ment.

It will be seen that a very important feature ot my invention is theapplication ol' a belt tightener to each ot a number ot sewing machinesdriven from a common shaft because thereby the driving belt in one ofthe Vmachines which needs adjustment to take up -merely to loosen thewing nut so as to alloiv the spring to act and then to tightenthe wingnut again; or in order to render the device automatic in its action atall times to take up slack or to keep the belt tight', the wing nut maybe lett loose or not employed; that is to say a construction may beemployed for pivotally attaching the rollercarrying bar not involvingthe use of a wing nut, in which ca se the stud or bolt 27 may beprovided with a slotted head, which may act either as a pivot or as aclamp, by use of a screwl driver, itdesired.

The belt tightener which'l provide for the belt running from the drivingshaft may also be made to work automatically by means ot a coil spring130 by having same connected at one end to the upper end of stem 21 andat the other end to some stationary point'on the table or box 22, asshown in Fig. 4. l i

Having thus'described my invention what l claim is:

l. The combination of the arm of a belt driven sewing mach'ine'having athreaded hole, a stud projecting horizontally from said hole and screwedtherein, a constantly acting belt tightener comprising a bar mounted onsaid stud, and clamping means for said bar.

a 2. The combination of a sewing` machine table; a. sewing machinemountedV thereon; a main driving shatt below 'th'eftable; a transmitterbelted -to said driving shaft, .and ineans torA transmitting power fromthe transmitter to the sewing machine, a belt tightenerextending yfrombelovv the table and reaching'above the table through the tabletop, 1 i'.Tjhe'comhination of. a. sewing machine table, aA sewing. maehineniuntedthereon, a

driving shaft, a transmittef under the table diivingly connected to saiddriving shaftv and belted to the sewing machine and a beltv tightenei"above the table top for the belt running from the tranemittei to thesewing machine and independent 0f the transmitter in its action.

4. 'Ihe Combination of a sewing machine table, a sewing machine mountedthereon, a main driving` shaft, a transmitter under the table belted tosaid driving shaft and belted to the sewing machine, a belt tightenereX- tending from the belt running from the driving shaft and reachingabove the table top, and a belt tightener above the table top for thebelt running from the transmitter to the sewing machine and independentof the transmitter in its action.

In testimony that I claim the foregoing I have hereunto set my hand.

SAMUEL F. STEIN.

